Recording medium and polysiloxane and resin mixture therefor



Nov. 13, 1962 E. M. BOLDEBUCK 3,063,872

RECORDING MEDIUM AND POLYSILOXANE AND RESIN MIXTURE THEREFOR Filed Feb. 15, 1960 T bermag/asf/c Lager Conduct/71g Layer mill/l g Ed/W? M. fio/debuck Her Afforney.

United States Patent Ofifice 3,063,872 Patented Nov. 13, 1962 3,063,872 RECORDING MEDIUM AND POLYSILOXANE AND RESIN MIXTURE THEREFOR Edith M. Boldebuek, Schenectady, N.Y., assignor to General Electric Company, a corporation of New York Filed Feb. 15, 1960, Ser. No. 8,587 30 Claims. (Ci. 117-211) This invention is concerned with compositions of matter and articles prepared therefrom useful in the recording, storing and reproducing of photographic images, technical data, etc. More particularly, the invention relates to compositions of matter comprising a solid, heat-deformable (i.e., thermoplastic), compatible mixture of ingredients comprising (1) an organopolysiloxane and (2) a solid aryl polymer selected from the class consisting of (a) polyarylene ethers, (b) a polystyrene, and mixtures of (a) and (b). The invention also embraces the use of the aforesaid compositions in making composite articles, for instance, tapes, sheets, slides, disks, etc., suitable for recording, storing and reproducing photographic images and technical data, employing the above compositions of matter as the thermoplastic layer in which such images and data are recorded, stored and reproduced.

The terms compatible and compatibility are intended to have the meaning established by the following criteria. The mixture of the organopolysiloxane and the aryl polymer, When dissolved in a suitable solvent such as xylene or toluene (in weight concentrations of from 1 to 30 percent) should constitute a homogeneous, transparent solution at room temperature (about 27 C.). In addition, as a second criterion, it is essential that when this solution is deposited in the form of a film or thin layer as is done in the case of the tapes hereafter described, and the solvent is removed, a homogeneous, transparent, optically clear film is again obtained. This solvent-free layer must remain transparent and show no evidence of haziness, even after repeated cycles of melting the thermoplastic composition and cooling it to the solid state, nor must it show any haziness even after long periods of storage at room temperature.

In the copending applications of William E. Glenn, Jr., Serial No. 698,167, filed November 22, 1957, now abandoned, and Serial No. 783,584, filed December 29, 1958, now abandoned, both of which are assigned to the same assignee as the present invention, are disclosed and claimed an electronic method and apparatus for recording, storing and reproducing photographic images and technical data. According to this method, technical data and photographic images are first converted electronically into coded signals. These signals are further reduced to variations in the intensity of a beam of electrons, and the electron beam with its negatively charged particles is used to scan a special surface so as to introduce onto this surface a pattern of negative charges (from the electrons deposited) which arrange themselves in accordance with the data or image to be recorded. This pattern of electric charges is essen tially the negative of the composite film, sheet, slide, etc., which is later developed by converting the pattern of electric charges on the heat-deformable layer to a pattern of depressions, ridges, etc., that can be observed optically.

This conversion can be achieved by heating the composite article or recording medium, particularly the surface thereof with, for instance, direct application of heat or by heat generated by radio frequency energy acting on a conducting layer, whereby the heat causes only the top thermoplastic negatively charged layer to fuse or melt, and 7 become liquid. When this happens, the negative charges are attracted to the conducting layer positioned under but not necessarily in contact with the thermoplastic layer, thus deforming the surface of the thermoplastic upper layer into various depressions, hills, ridges, etc. Thereafter, the heated surface is cooled or allowed to cool immediately to set or solidify these hills, ridges, and other deformations in the thermoplastic layer. The recording medium thus treated can now be read or projected visually by passing a beam of light through it in cooperation with a special optical system for conversion into an image or can be optically converted into the desired information or data in the form of electrical signals. The image can be viewed directly, projected on a screen, transmitted electronically for viewing on a television screen elsewhere, or can be simply stored on film. An additional description of the method for recording in the manner described above can be found in an article by William E. Glenn, Jr., in Journal of Applied Physics, December 1959, pages 1870-1873.

Because the thermoplastic layer is capable of being heated to the liquid state (at which time it develops the surface deformations by action of the induced electric field on a charged portion of the liquid and the pattern of ripples thus produced frozen into a permanent record by promptly cooling the liquid thermoplastic layer to the solid state), it is possible to employ such recording material many times over by merely subjecting the surface layer to the action of heat at a temperature high enough to cause fusion of the upper layer to a smooth surface, thus erasing the information stored in the aforesaid thermoplastic layer. In addition to the ability to reuse repeatedly the recording medium, the latter can also be employed as a master copy for duplication by techniques similar to phonograph disk stampings.

There are several requirements which are necessary for a satisfactory recording medium (recording medium or recording material will hereinafter be intended to mean the composite structure including the upper thermoplastic layer upon which the information is recorded and used in the electronic recording previously described, the base supporting layer and the conducting layer if it is part of the composite structure). In the first place, the recording medium must have optical clarity and must be transparent. It is preferably water-white (i.e., Water-clear) or only slightly tinted in thin films. Any trace of haze should be avoided in the recording medium because it will interfere with the later reading out or projection of any images which may have been introduced into the recording medium.

The recording medium must also have certain electrical characteristics, particularly it must be a good insulator and have high electrical resistivity; usually it is desirable that the specific resistivity be greater than about 10 ohmcentimeters when in the liquid state at the time it is heated to effect formation of any depressions or ridges or other deformations in the surface thermoplastic layer.

In addition, for certain applications, such as in tapes, the recording medium, including the surface thermoplastic layer, must be sufficiently flexible and strong to enable it to be rolled up around small diameters of about /8 inch to 1 inch mandrels. These are the usual requirements encountered in the case of projection machines, for instance, l6-millimeter projection machines which may be used to project the image on the screen.

The thermoplastic layer of the recording medium must be stable under moderate electron bombardment from the electron high voltage accelerating apparatus. The thermoplastic layer preferably has a maximum vapor pressure of 10* to l0 mm. Hg when in the liquid state, that is, when it is subjected to the elevated temperatures required to deform the thermoplastic layer of the recording medium in accordance with the charges thereon. The thermoplastic layer must also be stable at elevated temperatures at which it will be deformed by fperatures of at least 65 C., but should being converted to the'liquid or fused state at temperatures of at least about 85 C. depending on the suplsistant to temperatures well above 200 it is then possible to use thermoplastic compositions temperatures.

sharp melting point in order that the developing of the proper image on the thermoplastic layer proceed with "a minimum of control ditficulties. For a broad spectrum of use, the thermoplastic layer should be solid at tembe capable of porting backing layer. If the supporting layer is re- C. or higher,

havingsoftening or liquid points Well above the minimum 85 C. recited above. Since the recording medium may have backings which do not have the thermal resistance that some of the inflexible backings may have,

it is essential that the liquid temperature of the thermoplastic films be within a range of temperature somewhat lower than the temperature at which the backing itself may be fused or lose its'backing strength. "ing is, forinstance, an optically clear 'optically clear heat-resistant polymer such as an aromatic polyester or aromatic polyamide having a fusion temlf the backglass or some other perature above 150 C. or higher (as, for instance, those described in Journal of Polymer Science, volume 40, pages 289-418, November 1959), it is apparent that higher melting thermoplastic compositions can be employed within the scope of the invention.

Since the recording medium may comprise at least two layers and more often three layers, it is also essential that the thermoplastic layer have good adhesion to the backing material, whether it is the supporting backing or the conducting layer. Since one embodiment of the recording medium comprises a three-layer structure "composed of the backing material, the upper surface thermoplastic layer and an intermediate conducting layer (for instance, a thin film of metal, or of a metal oxide, or metal salt), it is additionally important that the thermoplastic layer have good adhesion to the conducting layer or the conducting surface.

As a further requirement, it is important in those cases where the recording medium will be in the form 'of a tape and thus will be rolled upon itself and stored,

that the thermoplastic layer be substantially free of cold flow that will cause any change in the configuration of 'the recorded information on the thermoplastic surface,

such as any depressions or hills or other deformations on the surface of the thermoplastic layer. Since the storage might take place under conditions where the temperature might rise to from 40 C. to 50 C., this cold flow must be non-existent or very low even at these 7 Any significant cold flow will magnify the storage problems to a point where the tape may not be capable of storage in reel condition as is the usual movie film. As a still further requirement, it is essential that the thermoplastic layer have good resistance towards oxygen attack so that it maintains high electrical resistivity during processing of the tape. Again, in those cases where a tape is involved, and because the tape may be rolled up on itself, it is also essential that the thermoplastic layer should be non-tacky and should not stick to any other surface with which it might come in contact in the rolled-up state.

Although the thermoplastic compositions described and employed'in the aforementioned applications of William E. Glenn, Jr., Serial Nos. 698,167 and 783,584 are satisfactory in many instances, it has been found that certain improvements would be desirable in connection with the use of such thermoplastic materials. In particular, it is desirable that there be a sharper fusion point to the liquid state of the thermoplastic layer; furthermore,th'e adhesion to the conducting layer underneath the thermoplastic layer should be improved.

'robiphenylyl, etc., radicals); etc.

Additionally, it has been found that the thermoplastic layer should be more flexible in those instances where the recording medium would be wound around small diameters such as in the case of spindles and sprockets used in projection equipment. As a still further area of improvement, the thermoplastic layer should resist adhesion to the adjacent back of the base layer when the film is in the rolled-up state, for instance, as a reel, or a spool, etc. Unexpectedly, I have discovered that all the above desired improvements are accomplished by employing as the thermoplastic layer for the recording medium a solid, heat-deformable mixture of ingredients comprising (1) an organopolysiloxane and (2) a thermoplastic solid (i.e., solid at room temperature) aryl polymer selected from the class consisting of (a) polyarylene ethers, (b) a polystyrene, and (c) mixtures of (a) and (b).

It is accordingly one of the objects of this invention to prepare a mixture of ingredients which can be used as a thermoplastic layer for recording, storing and reproducing photographic images, technical data, etc.

Another object of the invention is to prepare recording media in which the thermoplastic layer of such recording media is firmly adherent to the conducting substrate.

It is a still further object of the invention to prepare a recording medium in which the thermoplastic layer thereon is sufficiently flexible so as to be capable of being Wound around small diameters without cracking or in any way separating from the substrate to which it is applied.

An additional object of the invention is to prepare a recording medium in which the thermoplastic layer on which information will be recorded and stored will have no undesirable affinity for the base layer with Which it may come in contact in the rolled-up state.

Other objects of the invention will become more apparent from the discussion which follows:

One component of this thermoplastic composition is an organopolysiloxane having the formula RmSiO cals (e.g. phenyl, tolyl, ethylphenyl, biphenyl, naphthyl,

etc., radicals); aralkyl radicals (e.g., benzyl, phenylethyl, etc., radicals); haloaryl radicals (e.g., monochlorophenyl, tetrachlorophenyl, chloronaphthyl, fluoronaphthyl, dichlo- The organopolysiloxane can be of varying liquid viscosities (e.g., a viscosity of above 200 centistokes at 27 C.) or it can be solid at room temperature (e.g., at 2530 C.). When solid organopolysiloxanes are employed, they preferably should not soften at temperatures below 45 C., although higher softening organopolysiloxanes can be employed as long as they are thermoplastic. Whichever organopolysiloxane is used, it must be compatible with the aryl polymer in a suitable solvent (e.g., toluene, benzene, chloroform, etc.) and must also be compatible with the aryl polymer in the solvent-free state.

The aforesaid organopolysiloxanes can be prepared in various ways. One method comprises hydrolyzing the proper hydrolyzable organosilane or mixture of organosilanes having the formula II R SiX4,

acetoxy, or other hydrolyzable radicals. When using mixtures of hydrolyzable organosilanes, the average of n is such that the ratio of organic groups to silicon atoms of the final hydrolysis product is within the range set for m in Formula 1.

One particular method which can be employed for making these organopolysiloxanes involves hydrolyzing, for instance, a phenylchlorosilane, such as methylphenyldichlorosilane, or diphenyldichlorosilane either alone or with other organochlorosilanes, such as dimethyldichlorosilane, methyltrichlorosilane, phenyltrichlorosilane, etc. Thus, for instance, one can hydrolyze 90 mole percent diphenyldichlorosilane with about mole percent methy'ltrichlorosilane or dimethyldichlorosilane to obtain a resinous polymer which can be further condensed with suitable catalysts, such as alkali metal hydroxides (e.g., cesium hydroxide, potassium hydroxide, etc.), to obtain higher molecular weight products (e.g., from about 1000 to 10,000 molecular weight ebullioscopically measured in benzene) which can be so prepared to have softening temperatures of at least 45 C. if solid organopolysiloxanes are desired.

A still further way of making these organopolysiloxanes involves heating a cyclic organopolysiloxane, e.g., octaphenylcyclotetrasiloxane, tetramethyltetraphenylcyclotetrasiloxane either alone or with minor proportions of other cyclic polysiloxanes such as octamethylcyclotetrasiloxane, with an alkali metal hydroxide at elevated temperatures (e.g., 150-275 C.) until the desired molecular weight and hardness of the polydiphenylsiloxane or the methyl phenylpolysiloxane polymer are realized. In such instances, the amount of catalyst used will vary from about 0.001 to 0.1 percent, by weight, of the alkali metal hydroxide, based on the weight of the starting cyclic organopolysiloxane or polysiloxanes.

Another method for making these organopolysiloxanes comprises cohydrolyzing organosilanols, for instance, diphenylsilanediol with either phenylsilane triol or triphenyl silanol in such proportions as to give the desired ratio of organic groups to silicon atoms recited in Formula I. be found disclosed in US. Patents 2,258,218-222, issued Other methods for making these organopolysiloxanes may October 7, 1941, and assigned to the same assignee as the present invention, and in US. Patent 2,482,276, issued September 20, 1949.

One important group of organopolysiloxanes which can be employed in the practice of the present invention are liquid organopolysiloxanes (of from 200 to 1000 centistokes or more at about 35 C.) coming within the generic organopolysiloxane Formula I recited above. These liquid organopolysiloxanes correspond to the general formula l L it where R represents the same or different monovalent organic radicals (many examples of which have been given above), at least 40 percent of the total number of monovalent organic radicals being aryl groups, and s is a whole number equal to at least 1, for instance, from 1 to 10,000 or more. These fluids can be obtained, for instance, by equilibrating, i.e., heating, a hexaorganodisiloxane and a cyclic organopolysiloxane, for instance, hexamethyldisiloxane with tetramethyl tetraphenylcyclotetrasiloxane in the presence of a catalyst such as sulfuric acid. More particular directions and additional descriptions of compositions coming within the scope of the above Formula IA may be found in Patnode US. Patents 2,469,888 and 2,469,890, issued May 10, 1949, and assigned to the same assignee as the present invention.

An organopolysiloxane which has been found especially useful for combination 'with the aryl polymers to make the thermoplastic compositions comprises a linear methyl phenylpolysiloxane coming within the scope of Formula IA wherein mole percent of the organopolysiloxane units are methyl phenylsiloxy units of the formula and 10 mole percent are trimethylsiloxy units of the formula Such a composition can be made by interacting in suitable molar concentrations hexamethyldisiloxane and tetramethyl tetraphenylcyclotetrasiloxane at elevated temperatures in the presence of sulfuric acid under the conditions recited in the aforementioned two Patnode patents. The product is advantageously devolatilized to remove low boiling polymers and to obtain a methyl phenylpolysiloxane fluid of between 500-600 centistokes when measured at about 35 C. This methyl phenylpolysiloxane (hereafter so designated) was employed for making certain thermoplastic compositions described in the examples which follow.

A still further class of organopolysiloxanes which can be employed in combination with the aryl polymers are soluble (e.g., in benzene) organopolysiloxanes having an intrinsic viscosity in benzene at 25 C. of at least 0.1 deciliter per gram in which from 90 mole percent of the organosiloxy units are of the formula RSiO where R is an aryl radical, and the remaining organosiloxy units, if any, being selected from the class consisting of diorganosiloxy units (e.g., dimethylsiloxy, diphenylsiloxy, methyl phenylsiloxy, etc., units),monoalkylsiloxy units in which the alkyl radical has from 1 to 4 carbon atoms. examples of such compositions are more particularly disclosed and claimed in the copending applications of John F. Brown, Jr., and Lester H. Vogt, Jr., Serial No. 788,069 (now US. Patent 3,017,386 issued January 16, 1962), and of Murray M. Sprung, Serial No. 788,068 (now U.S. Patent 3,017,385 issued January 16, 1962), both filed January 21, 1959, and both assigned to the same assignee as the present invention. By reference these applications are made part of the disclosures of the instant application.

One method for making these polymers comprises hydrolyzing a phenyltrichlorosilane solution in diethyl ether with water, isolating the hydrolyzate from the solvent, dissolving it in an aromatic solvent such as benzene, and thereafter removing essentially all the water by azeotropic distillation. A high boiling solvent such as diphenyl or diphenyl ether (or mixtures of these two solvents) is then combined with the hydrolyzate (called a pre-polymer" of monophenylsiloxane), a small amount of KOH added, and the ingredients heated to about 250 C. while at the same time removing any residual water and benzene. After the mixture is allowed to cool, a white solid material is obtained which is advantageously dissolved in benzene and the KOH neutralized with a small amount of an acid such as acetic acid. The solution is then poured into a suflicient amount of methanol to precipitate the polymer which is then washed with water and an additional amount of methanol, and air dried. A polymer made this way has an intrinsic viscosity in benzene which may vary from 0.1 to as high as 4.0 and the molecular weight may even be as high as 4 million when determined by light scattering. This polymer has the formula 6 5 1.5)x where x is an integer greater than 1. The polymer is quite heat resistant, but nevertheless is soluble in benzene, and when cast into film is transparent and flexible, exhibiting good tensile strength. A particular method for making this particular polymer (having an intrinsic viscosity of 0.1) is found in Example 2 of the aforesaid Brown and Vogt application and in Example 2 of the aforesaid Sprung application and is the polymer which was employed in one of the following examples, specifically Example 10.

Preferably, in making the organapolysiloxane, it is desirable that at least 75 percent of the R groups be aryl radicals, for instance, phenyl radicals, and that the remainder of the R groups, if any, be selected from the class consisting of alkyl, haloaryl, and aralkyl radicals, many examples of which have been given above. The method of manufacture, the type of organic groups bonded by C-Si linkages present in the organopolysiloxane, the ratio of the organic groups to silicon atoms, and the degree of condensation, are all factors to be considered in the determination of the proper molecular weight and properties of the organopolysiloxane which will be used to make the thermoplastic compositions. Persons skilled in the art will have no difiiculty in selecting the proper organopolysiloxane composition or compositions for combination with the aryl polymer. Obviously, other methods may be employed for making the aboveidentified organopolysiloxanes employed in making the aforesaid thermoplastic compositions.

The polystyrene materials which are employed in the practice of my invention are polymers of a styrene either unsubstituted or substituted with groups which do not undesirably lower the electrical resistivity of the polymer. Such styrenes may have the formula III where Z is a member selected from the class consisting of hydrogen, halogen (e.g., chlorine, bromine, fluorine, etc.), an alkyl radical (e. g., methyl, ethyl, propyl, isopropyl, butyl, octyl, etc.), alkoxy (e.g., methox ethoxy, propoxy, isopropoxy, butoxy, etc.), and p is a whole number equal to from to 3. Preferably, the starting monomer comprises styrene. For brevity, the term a polystyrene or the polystyrene material will include not only the unsubstituted polystyrene (made from styrene) but also polystyrene substituted with various substituents, e.g., those for which Z stands, as well as copolymers of a styrene of the above formula.

Advantageously, I have found good results are obtained if the polystyrene material has a molecular Weight within the range of from about 2,000 e.g., from 10,000 to 100,000 when measured by osmotic pressure in chloform, although other molecular weights may be employed. Also, the polystyrene material advantageously has a softening range of from about 75 C. to 150 C., while the intrinsic viscosity in chloroform is preferably Within the range of from about 0.05 to 1.0 deciliter per gram. Polystyrene materials of this type can be readily prepared by polymerizing the monomeric starting material with an organic peroxide, such as benzoyl peroxide; in organic peroxide materials, such as sodium persulfate, either in solvent or in aqueous emulsion media, until such time as the desired molecular weight is obtained. Methods for producing such types of polystyrenes are well known in the art and require no description. However, directions for making polystyrene may be found in the book"Synthetic Resins and Rubbers" by Paul 0. Powers, published by John Wiley and Sons, New York, NY. (1943), pages l58l65. The term a polystyrene in addition to including unsubstituted and substituted polystyrenes, that is, polystyrenes that are prepared from styrene monomers substituted, for instance, in the ortho, para, meta, symmetrical, and asymmetrical positions by any of the substituent recited previously, is also intended to include copolymers of a styrene where the styrene residue preferably but not essentially predominates, for instance, copolymers of butadiene-1,3 and styrene; ethyl acrylate and styrene, etc., where the monomers other than where W stands for a divalent arylene radical, either substituted or unsubstituted and q is a while number equal to at least 10 or more, e.g., up to 10,00 or more. Thus, W can be phenylene, chlorophenylene (e.g., from 1 to 4 nuclearly substituted chlorine atoms), naphthylene the tolylene radical, etc. A group of aryl polymers which can be advantageously employed in the practice of my invention comprises those having the general formula wherein the oxygen atom of one unit is connected to the benzene nucleus of the adjoining unit, q is a positive integer equal, for instance, to at least 10 (e.g., from to 5,000 or more), Q is a monovalent substituent selected from the class consisting of hydrogen, aliphatic hydrocarbon radicals free of a tertiary alpha-carbon atom (e.g., methyl, ethyl, propyl, isopropyl, butyl, etc., radicals), halogen (e.g., chlorine, bromine, fluorine, etc.), aralkyl, alkaryl, and aryl radicals, Q is a monovalent substituent which may be the same as Q and in addition may be a hydrocarbonoxy radical free of an aliphatic tertiary alpha-carbon atom, etc. Examples which Q and Q may be correspond to the various examples of radicals which R may be (e.g., alkyl, aryl, aralkyl, alkaryl, etc.) in the organopolysiloxane of Formula I. Typical examples of monovalent hydrocarbonoxy radicals are, for instance, methoxy, ethoxy, propoxy, butoxy, phe-noxy, ethylphenoxy, tolyloxy, etc., radicals.

These phenylene polymers may be prepared in various ways. One method comprises oxidizing a phenol represented by the formula VI (I)H where Q and Q have the meanings from above. These phenols are oxidized by passing an oxygen-containing gas (for example, oxygen itself or air) through the particular phenol in the presence of a catalyst system comprising a cuprous salt and a tertiary amine. More specific directions for preparing these polyphenylene ethers as well as examples of starting materials and polymers prepared therefrom are disclosed and claimed in the copending applications of Allan S. Hay, Serial No. 744,086, now abandoned, and Jack Kwiatek, Serial No. 744,087, both filed June 24, 1958, and assigned to the same assignee as the present invention. By reference, these two applications are made part of the disclosures and teachings of the instant application in order to avoid undue prolixity in reciting the starting ingredients, the catalyst systems, the conditions, as well as the various radicals which the substituents in the above general formulas may represent.

Other phenylene ethers can be employed in the practice VII where A is a member selected from the class consisting of oxygen and isopropylidene; each r is a or a whole number from 1 to 3, and Bs are tertiary butyl or alphacumyl groups at least one-third of the As being in the meta position. Specific directions for preparing these types of compositions are found and disclosed in Belgian Patent 573,694, issued December 8, 1958.

The proportions of the ingredients employed in the practice of the present invention may be varied widely. Generally, I prefer to employ, on a weight basis, from about to 98 parts of the organopolysiloxane to 2 to 90 parts of either the polystyrene ingredients or the arylene polymer or mixtures of the latter two ingredients. Thus, when making mixtures of the organopolysiloxane and arylene ether polymer, I may use from about 50 to 98 parts of the organopolysiloxane and from 2 to 50 parts of the arylene ether polymer. When making mixtures of the organopolysiloxane and the polystyrene, under many conditions I prefer to employ from 10 to 90 parts of the organopolysiloxane to 10 to 90 parts of the polystyrene material (or mixtures of polystyrenes).

Alternatively, I may employ all three ingredients in the form of a mixture of the organopolysiloxane, the polystyrene, and the arylene ether polymer. In such instances, on a percentage weight basis, I may use from 2 to percent, by weight, of the arylene ether polymer, from 2 to 60 percent of the polystyrene, and from to 95 percent of the organopolysiloxane, the total per-- cents being equal to 100 percent. By varying the proportions of ingredients in the thermoplastic composition, it is possible to vary the melting or liquid point of the latter.

The backing material for the recording medium may be either a flexible composition or may be a rigid inflexible material. Examples of rigid materials which can be employed (keeping in mind that optical clarity, heat resistance, and radiation resistance are usually the required properties) are, for instance, glass (in the form of plates, slides, disks, etc.); unsaturated polyester resins (formed from the reaction of a polyhydric alcohol, such as ethylene glycol, diethylene glycol, propylene glycol,

'dipropylene glycol, etc., and an alpha-unsaturated alphabeta-dicarboxylic acid or anhydride, for instance, maleic acid, maleic anhydride, fumaric acid, citraconic acid, etc.) combined with these unsaturated polyesters one may also incorporate such copolymerizable cross-linking ingredients, such as diallyl phthalate, diethylene glycol dimethacrylate, etc. One can also employ metals such as aluminum, nickel, chromium, etc., where the metal serves both as a conducting layer and as a reflective surface which can be read optically by reflection.

Examples of flexible materials which can advantageously be employed as the backing material are, for instance, polyethylene terephthalate (which can be obtained by the transesterification of esters of terephthalic acid with divalent alcohols, for example, ethylene glycol as shown in U.S. Patent 2,641,592Hofrichter), such polyethylene terephthalate being sold by E. I. du Pont de Nemours and Company of Wilmington, Delaware, under the name of Mylar. A more refined grade of polyester terephthalic acid tape or film found highly appropriate as the basis for recording images (and which contains small intercondensed residues from dihydric alcohols, such as, propylene glycol-1,3 to reduce crystallinity) is sold under the name of Cronar.

Another backing material which can be used advantageously because of its good heat resistance, strength,

inertness and resistance to radiation are polycarbonate resins corresponding to the formula a t Y a 0 VIII il Till Lt $104k.

L JW where R is hydrogen or a monovalent hydrocarbon radical, many examples of which have been given above for R (where more than one R is used, they may be the same or different); R is selected from the class consisting of divalent alkylene and alkylidene residues (e.g., methylene, ethylene, propylene, propylidene, isopropylidene, cyclohexylidene, etc.), oxygen, etc.; C is the residue of an aromatic nucleus (e.g., benzene naphthalene, biphenyl, etc. nucleus); Y is a substituent selected from the group consisting of (a) inorganic atoms, (b) inorganic radicals, and (0) organic radicals, (a), (b) and (c) being inert to and unaffected by the reactants and reaction conditions, 2 is a whole number equal to from 0 to a maximum determined by the number of replaceable nuclear hydrogens substituted on the aromatic hydrocarbon residue C; t is a whole number equal to from 0 to a maximum determined by the number of replaceable nuclear hydrogens on R and w is a whole number equal to from 0 to l, inclusive. These compositions and directions for preparing these compositions are disclosed and claimed in the copending application of Daniel W. Fox, Serial No. 520,166, filed July 5, 1955, and assigned to the same assignee as the present invention. By referonce, this application is made a part of the disclosures and teachings of the instant application It will be apparent to those skilled in the art that other compositions may be employed as backing materials where the softening point is sufiiciently high so as to allow heating of the thermoplastic layer without adversely affecting the base layer.

In many instances, there is interposed between the thermoplastic surface and the backing, a conducting layer which can be subjected to radio frequency energy as a means for heating the thermoplastic layer. This conducting layer acts as the layer which becomes positively charged beneath the thermoplastic layer and when the thermoplastic layer is heated to cause the thermoplastic material to become fluid and deformable, the deposits of negative charges on the top of the thermoplastic layer are attracted to the positively charged conducting layer, thus deforming the thermoplastic surface of the film. Among such conducting layers (which should be thin enough to be optically clear if interposed between the base and the thermoplastic layer) may be mentioned the various metals, for instance, iron, chromium, tin, nickel, etc.; metallic oxides, such as stannic oxide, cuprous oxide, etc. salts, for instance, cuprous iodide, etc. In using the conducting layer, it is essential that the layer of metal or metal compound applied to the base layer" be no thicker than is required to obtain a transparent film thereon. For this reason, it has been found that the metal film is advantageously of the order of about 1'0 to Angstroms (A.) or 0.001 to 0.01 micron thick, and that it should have a resistivity of between 1,000 and 10,000 ohms per square centimeter for optimum radio frequency heating if that is the method used for developing the deformation pattern.

The thickness of the thermoplastic layer can vary widely but advantageously is approximately 4 to 20 microns thick. The base layer thickness can also vary widely as long as it has the proper electrical and radiation resistance flexibility, strength, heat resistance, etc.; this base layer can be from a few microns in thickness to as much as 50 to 400 microns or more in thickness.

The conducting layer is advantageously applied to the backingvby the well-known method of volatilizing the metal or metal compound in a vacuum at elevated temper-atures and passing the backing in proximity to the vapors of the metal or metal compounds so as to deposit .an even, thin, optically clear, adherent film of the metal or metal compound on the backing and preferably while the entire assembly is still under vacuum. One method for applying a metal salt conducting layer to the backing, e.g., polyethylene terephthlate, is found in US. Patent 2,756,165Lyon. Thereafter, a solution of the thermoplastic composition is applied to the surface of the con ducting layer, and the solvent evaporated to deposit a thin film of the thermoplastic composition on the conducting layer.

The particular solvents employed for the thermoplastic composition may be varied Widely and will depend on the type of polymers and resinous compositions employed in the mixture of ingredients. Included among such solvents are aromatic hydrocarbon solvents, e.g., toluene, xylene, benzene, etc. Solids weight concentrations of from to 30 percent of the thermoplastic composition in the solvent are advantageously used.

In the accompanying drawing, the single FIGURE shows a tape recording medium composed of an upper thermoplastic layer 1 comprising a mixture of the organopolysiloxane and arylpolymer, a base member 2 supporting the thermoplastic layer, and an intermediate conducting layer 3.

In order that those skilled in the art may better understand how the present invention may be practiced, the following examples are given by way of illustration and not by way of limitation. All parts and percents are by weight unless otherwise noted.

The organopolysiloxane polymer employed in most of the following examples was a diphenyl silicone polymer (hereinafter so designated) obtained by melting 600 parts octaphenylcyclotetrasiloxane in a flask under nitrogen sparge and when the liquid polysiloxane was at a temperature of about 230 C., 1 part cesium hydroxide was added and while stirring, the temperature was slowly in.- creased to 260 C. for 1 hour. A second portion of 0.5 part cesium hydroxide was added and heating was continued at 260270 C. for 1 /2 hours longer. At this time, a small amount of iodine was added to the hot reaction mixture until the purple color was no longer present evidencing that the cesium hydroxide was completely neutralized. The excess iodine was allowed to sublime, and the reaction mixture was then cooled to about 125 C. and 433 parts toluene was added and stirred into the viscous melt. The solution was allowed to stand for 72 hours and the crystalline material that formed was filtered off. Residual solvent was then removed from the polymer by distillation at atmospheric pressure followed by distillation in vacuum at about 125 C., with a slow stream of nitrogen passing through the viscous melt to remove the final trace of solvent. This yielded a hard transparent diphenyl polysiloxane polymer having a molecular weight of approximately 1275 by ebullioscopic measurement in benzene. The polymer melted to a liquid at around 80 C.

The polystyrenes used in the following examples were obtained by polymerizing styrene and were obtained from Dow Chemical Company and were identified by the following properties:

Liquid Number 2 Polystyrene Designation Temp, [1,] Average C. Mole Wt.

1 In chloroform, dcciliters/gram.

1 By osmotic pressure, in chloroform.

3 This figure was obtained by extrapolation from intrinsic viscosities and molecular weights of other polystyrenes.

12 (Cu Cl about 19.8 parts benzene and 23 parts pyridine. During the course of the reaction the temperature was held to a maximum of 40 C. After the reaction, the mixture was diluted with 616 parts benzene and the product was precipitated by pouring the reaction mixture into about 2014 parts methanol containing about 8 parts HCl, and the polymer was then separated by filtration. The product poly-(2,6-dimethyl-1,4-phenylene) ether was characterized by the recurring structural unit of the formula I r l -Q l... 3

This product (which will hereinafter be identified as phenylene ether polymer) had a melting point in ex cess of 250 C. It was soluble in such solvents as benzene, toluene, xylene, and chloroform.

In order to evaluate the various formulations coming within the scope of the present invention as a thermoplastic medium -for recording information and images pursuant to the inventions disclosed and claimed in the above-identified Glenn applications, thermoplastic compositions were prepared by applying a dilute (about 10 to 25 weight percent) toluene solution of the thermoplastic material directly on the surface of a 30 mm. wide by 0.004 inch thick optical grade polyethylene terephthalate tape sold as Cronar by E. I. du Pont de Nemours and Company (methods for preparing such film may be found disclosed in such patents as US. 2,678,285 and 2,698,241). These solutions were also applied to a conducting, transparent layer in turn superposed on the polyethylene terapht-halate base. After air drying at room temperature, the sample piece was heated for about 1-0 to 15 minutes either in an air circulating oven about 150 C. or on a hot plate held at a temperature just below the heat distortion point of the polyethylene terephthalate (approximately 140 C.). At this point the samples were tested for adhesion and flexibility of the thermoplastic layer to the polyethylene terephthalate backing or to the metal conducting layer, in many instances after they had been inscribed by an electron beam in accordance with the above-described Glenn process.

The actual writing on the thermoplastic surface (which was about 7-12 microns thick) was carried out as follows. An electron gun was mounted in a bell jar which fitted on an O-ring set into a horizontal base plate. When there was no intervening metallic layer, the sample film or slide was placed on a small metal plate which was permanently centered under the beam filament and which served as ground and as the heating element later used to effect deformation of the thermoplastic surface. The bell jar was set in place and the system was then evacuated. When the required high vacuum had been obtained, the metal plate carrying the sample was heated electrically to the desired temperature and the molten thermoplastic was then exposed to the electron beam. The electron beam was adjusted to sweep back and forth once in a linear path, irradiating an area 4 inches long and approximately 6 mils wide in a time interval of of a second. In the standardized test conditions, the beam was operated at a current of 0.1 microamp and with a 15 kv. potential drop from filament to the sample holder (ground plate). In the single flash of second duration, 2 10 electrons were delivered to a traced area of 0.024 square inch.

When a tape was employed using an intervening conducting layer, the tape was exposed directly to writing by an electron beam under vacuum similarly as was done in the Glenn application and by radio frequency heating, the charged layer was melted and the surface deformed to give the required deformations.

The optical clarity was determined by visual appearance and any trace of haziness was considered unacceptable although a faint colorat on of film was not considered too detrimental. The flexibility of the film containing the thermoplastic layer was determined by bending it around a 1-inch diameter cylindrical mandrel and then examining the thermoplastic coating under a 30X microscope for crazing, cracking or lifting from the base polyethylene terephthalate. If no damage could be seen, the test was repeated on inch diameter cylinder and if again satisfactory, the flexibility of the film was considered acceptable.

EXAMPLE 1 In this example, 91.4 percent of the above diphenyl silicone polymer, 1.5 percent of the dimethyl phenylene ether polymer, 5.8 percent of polystyrene Q-7, and 1.3 percent m-terphenyl (as a plasticizer) were intimately mixed together in a toluene solvent. When a sample of this solution was treated to remove solvent the solid residue was found to have a melt viscosity, that is, melted to the syrupyfluid state, within the temperature range of about 95-105 C. A percent toluene solution of this blend was applied to one surface of a clear polyethylene terephthalate tape. The solvent was removed by first airdrying at room temperature and then heating at about 100-l40 C. to insure all solvent was removed. This tape was then placed in an electron beam in the manner as described above and more particularly recited and claimed in the aforementioned Glenn patent applications and was subjected to electron recording under vacuum. The charges on the thermoplastic layer were developed by passing the uncoated polyethylene terephthalate surface over a heated drum. The thermoplastic layer was allowed to cool to set or freeze the deformations in the surface of the thermoplastic layer. The information on the tape could be read out with the optical system described again in the aforementioned Glenn applications. The thermoplastic layer and the films made therewith were optically clear, and had the proper electrical resistivity, toughness and flexibility, as well as adherence to the base polyester layer. The melt viscosity was within the desired temperature range particularly with respect to the heat distortion temperature of the polyethylene terephthalate backing. One advantage of this material was that it'could be rolled up on itself and even at temperatures as high as 50 C., there was no perceptible cold flow which in any way affected the information recorded by means of the deformations on the surface of the thermoplastic layer nor was any sticking observed between the thermoplastic surface and the polyethylene terephthalate in the rolled-up state.

EXAMPLE 2 In this example various proportions of the diphenyl silicone polymer and the dimethyl phenylene ether polymer were mixed together according to the following table:

1 Was mobile syrupy liquid.

Each of these mixtures of ingredients was dissolved in .toluene in the form of a weight percent solution.

Transparent polyethylene terephthalate tape was coated on one side with a thin (about 10 Angstroms) transparent coating of chromium (using the vapor deposition "method) under high vacuum of about 0.1 micron and elevated temperatures ofaround ll00l200 C. The toluene solution was then applied to the chromium surface on the polyethylene terephthalate base. The thickness of the thermoplastic layers in each case was about 6 to 7.5 microns. The solvent was removed from the coated tapes as was done in Example 1. Each of the thermoplastic layers was flexible, adherent to the backing and optically clear. Tapes with 2A, 2B, and 2D as the thermoplastic surface layers were subjected to inscription by an electron beam and thereafter heated to the liquid temperature of the thermoplastic layer, and the recorded information was then set by cooling the deformed liquid thermoplastic layer to room temperature. This information could be read out similarly as was the composition described in Example 1. The adhesion of the thermoplastic layer to the chromium conducting layer and the flexibility of the tape itself in each instance was good.

EXAMPLE 3 In this example formulations were prepared from the diphenyl silicone polymer and the various polystyrenes recited above. The thermoplastic composition (ultimately dissolved in toluene in the form of 25 weight percent solution) had the following properties and was composed of the following ingredients which are expressed in weight percent:

Table II Percent Percent Polystyrene No. Diphenyl Liquid Silicone Temp, Polymer PS-l PS-Z Q,7 C.

1 Tested with glass slide backing instead of polyethylene terephthalate In.

Each of the above formulations (with the exception of 3F which was applied directly on a glass slide) in the form of a toluene solution was applied to the conducting metal surface of a polyethylene terephthalate tape containing as the conducting sufrace a thin transparent coating of chromium of the same thickness and applied in the same way as in Example 2. The thermoplastic layers comprised thicknesses of between 7.510,a and had all the desirable properties recited previously. Each of the tapes and the coated glass slide could be inscribed with an electron beam similarly as was done before and found to be eminently suitable for electron beam recording and could be readily read out with the proper optical apparatus. The thermoplastic layers had the desirable properties enumerated above.

EXAMPLE 4 particularly, the following table shows the mixture of ingredients as prepared from the aforesaid three ingredients in which all percents are by weight:

Table III Percent Percent Percent Formulation Dinhenyl Polystyrene Phenylene Liquid No. Silicone Ether Temp.,

Polymer Polymer 0.

Again, each of these thermoplastic compositions in the form of a 25 percent weight toluene solution was applied to the conducting surface of a tape comprising a polyethylene terephthalate backing in which the conducting surface was a transparent thin layer of chromium similarly as in Example 2. After removing the solvent as was done in the other examples, it was found that all the tapes met the requirements of clarity, flexibility, adherence, etc. The tapes made with thermoplastic compositions 4D and 4E were subjected to electron beam recording and thereafter the information was developed and set by means of the application of a blast of hot air to the charged thermoplastic layer, and cooled. The stored information could be read by means of the optical equipment described in the aforesaid applications of William E. Glenn, Jr.

EXAMPLE In this example, thermoplastic compositions were prepared similarly as was done in Examples 1 and 2 employing the component blends of the diphenyl silicone polystyrene and the phenylene ether polymer, and in addition the m-terphenylused in Example 1. The following table shows the proportions of ingredients used in each instance.

Table IV Percent Percent Percent- Dimothyl No. Diphenyl Poly- Phenylene m-lerphenyl Silicone styrene Ether Polymer Q.7 Polymer 5A. 88. 4 7. 8 2.0 1. 8 5B 92. O 5. 3 1. 4 1. 3

Each of the ingredients in Samples 5A and 5B was formulated into 25 weight percent toluene solutions, and applied to a thin optically clear layer of cuprous iodide (about 100 Angstroms thick) deposited on a polyethylene terephthalate backing. After removing the solvent as was done previously, each of the tapes thus obtained was subjected to electron beam recording and the charged thermoplastic surface was heated to effect deformation of the liquid surface and thereafter cooled to set the deformations in the thermoplastic layer. Each of these tapes could be readily introduced into a read-out apparatus similarly as was done in connection with the tapes produced in the previous examples and the information could be read back in accordance with the procedures recited in the above-mentioned Glenn patent applications.

EXAMPLE 7 In this example, a tape comprising a backing of polyethylene terephthalate, a thin conducting layer (about A. thick) of iron, and a thermoplastic layer comprising the thermoplastic composition as described in Example 1 was subjected to inscription by an electron beam, the thermoplastic surface temperature raised by radio frequency heating of the conducting iron layer, and thereafter immediately cooled to give an information storage in such thermoplastic layer which could again be read back with an optical projection system and could be stored as a permanent record, or could be erased by raising the temperature of the thermoplastic layer, and could even be used as a master copy for duplication in making other thermoplastic films similarly as employed in those techniques used to make phonograph disk stampings.

EXAMPLE 8 This example illustrates the preparation of a compatible thermoplastic composition useful for making the tapes more particularly described in the foregoing examples employing a copolymer of styrene and butad-iene as one of the ingredients of the thermoplastic layer. More particularly, 70 weight percent of a copolymer of 16 butadiene and styrene (in which the butadiene comprised about 15 weight percent of the total weight of the styrene and butadiene-l,3 employed prior to copolymerization and sold by Goodrich Rubber Company as Goodrich Resin No. 50) in the form of a Xylene solution, was mixed with 30 weight percent of the diphenyl silicone recited above in the form of a toluene solution. This compatible mixture was so adjusted that it was in the form of a 2 weight percent xylene-toluene solution. This solution was applied to a polyethylene terephthalate backing similarly as was donein Example 1. The thermoplastic layer had a mobile liquid point of about C. This thermoplastic layer was inscribed with an electron beam similarly as above but the temperature of the thermoplastic layer was maintained at around its liquid point during inscription. Thereafter the layer was allowed to cool. This inscribed tape could be read with the optical system described in the aforesaid Glenn applications.

EXAMPLE 9 In this example a mixture of ingredients was blended together from 37.5 parts polystyrene PS-l, 37.5 parts polystyrene PS2, 6.2 parts of the dimethyl phenylene ether polymer and 18.8 parts of the liquid methyl phenylpolysiloxane previously described having a viscosity of about 500600 centistokes at about 35 C. This blended mixture was-readily converted to the liquid state at a temperature of about C. A toluene solution of this blend of ingredientswas deposited on the chromium coated side of a polyethylene terephthalate tape similarly as was done in the previous examples and the solvent removed to leave a thermoplastic layer thickness of about 810p.. Thereafter this tape was inscribed with an electron beam similarly as was done in the preceding examples and the inscription was projected on a screen to establish that a sharp image had been obtained by means of this particular thermoplastic composition and the tape made therefrom.

EXAMPLE 10 In this example a blendof ingredients was prepared from 43.65 parts polystyrene PS1, 43.65 parts polystyrene PS-2, 3 parts of the above-described liquid methyl phenylpolysiloxane, and 9.7 parts of a phenylpolysiloxane (of intrinsic viscosity 0.1 in benzene) having a ratio of one phenyl group per silicon atom prepared in accordance with the disclosures in the aforesaid Brown and Vogt and Sprung patent applications. This mixture of ingredients had a mobile liquid (syrupy) point of about 133 C. A toluene solution of the aforesaid mixture of ingredients was employed to deposit a film 0n the chromium side of a chromium-coated polyethylene terephthalate film and the solvent removed similarly as was done in the previous examples. This tape could be inscribed similarly as in the preceding examples and then could be projected to give a sharp image.

It will, of course, be apparent to those skilled in the art that in place of the dimethyl phenylene ether polymer, and the diphenyl polysiloxane and the methyl phenylpolysiloxane of the previous examples, one can employ other phenylene ether polymers and organopolysiloxanes, many examples of which have been given previously, without departing from the scope of the invention. In addition, the polystyrene material instead of being polystyrene itself. can be polymers and copolymers of a styrene of the formula given above.

In formulating the thermoplastic composition, certain precautions should be observed. No component comprising the thermoplastic compositions should by its very constitution or by groups present therein be a cause of adverse electrical properties in the thermoplastic composition as, for instance, should they be the cause of excess surface leakage of electrical charges induced by the electron beam during inscription. This would, therefore, preclude the presence in any of the components of the thermoplastic composition and layer of any significant amounts of strongly polar groups such as the nitro group, the hydroxyl grou etc. However, it should be recognized that the presence of small amounts of siliconbonded hydroxyl groups, for instance, less than about 1 percent, in the organopolysiloxane is acceptable and is substantially non-detrimental to the electrical sensitivity of the thermoplastic composition in which the organopolysiloxane is incorporated.

Finally, as a further precaution in formulating the thermoplastic composition and recording media using such thermoplastic compositions as the thermoplastic la er, there should be no component present in the thermoplastic compositions which volatilizes or in any other way changes in any significant amount its proportionate relationship during preparation of the thermoplastic material and its processing on the base member, particularly, When applying the thermoplastic composition to the surface of the conducting layer on the backing member. Thus, when making solutions of the thermoplastic composition, no component should be present therein which will undesirably volatilize during those steps where solvent is removed by heating or under vacuum, and where the recording medium is subjected to heating (for instance, by a direct application of a current of hot air or by radio frequency heating) at the time that the electrical charges on the surface of the thermoplastic layer are deformed to develop the pattern capable of being read by suitable optical apparatus.

The proportions of ingredients can obviously be varied widely as pointed out earlier without departing from the scope of the invention. In many applications the organopolysiloxane component of the thermoplastic compositions used for making the recording media herein described and claimed, comprises a major weight proportion of the ingredients in the thermoplastic layer. This, of course, does not preclude the possibility of the thermoplastic composition containing less than 50 weight percent of the organopolysiloxane, e.g., from to 40 weight percent. In determining the amount of organopolysiloxane used with the aryl polymer, suitable attention should be paid to the type of backing employed particularly the heat resistance and heat distortion temperature of such backing, the type of organopolysiloxane used, as well as the particular aryl polymers or mixtures of aryl polymers employed. One important criterion is that the liquid temperature at which deformation can be most readily accomplished be a practical one consistent with the requirements of the system being used for recording information and data, developing such information and data in the form of deformations on the thermoplastic layer, and thereafter projecting such information and data by a suitable apparatus.

Various modifying agents which do not adversely affect the properties required for the thermoplastic recording medium can be employed, as for instance, various plasticizers to raise or lower the liquid or melting point of the thermoplastic layer, etc. In place of the polyethylene terephthalate other backings can be employed, as for instance the polycarbonate resins heretofore recited.

The thermoplastic compositions and tapes made therewith can be employed in various applications and are particularly useful for recording of computer information. In addition, they can be used in the movie film industry whereby these tapes can be used to record the action being filmed and the image can be processed immediately after the action has been recorded on the film and by suitable optical apparatus transferred and projected to determine whether the action which was taken with the film is acceptable and satisfactory for final showing.

Additional directions for using recording media of the type described in the instant application can be found in the copending application of William E. Glenn, Jr.,.Serial No. 8,842, filed concurrently herewith and assigned to the same assignee as the present invention, this latter 18 application being a continuation of the earlier Glenn applications Serial Nos. 698,167 and 783,584 referred to previously.

The term thermoplastic composition or allied terminology is intended to mean a composition which can be heated at its fusion or liquid forming temperature repeatedly without any significant change in the temperature of fusion or liquefication after each succeeding cycle of heating. The term thermoplastic composition is primarily intended to apply to the combination of the organopolysiloxane and the aryl polymer. However, in some instances the term thermoplastic composition will be used when referring to either the organopolysiloxane or aryl polymer.

The developing temperature, i.e., the temperature at which the charges on the thermoplastic layer effect deformation of the surface of the thermoplastic layer, was obtained in several ways as shown in the preceding examples. One method comprised applying a current or blast of hot air to the surface of the charged thermoplastic layer where the temperature ciently high to effect liquefication of the thermoplastic layer to the desired degree of fiowability to cause the deformation on the surface thereof; another method comprised using radio frequency heating to arrive at the proper temperature for causing deformation of the surface of the thermoplastic layer; and finally, particularly when a tape was employed, the tape was passed over a heated drum maintained at the proper temperature wherein the surface of the base member furthest from the thermoplastic layer was in direct contact with the heated drum so that heat diffused upward through the tape to the thermoplastic layer to cause the above-mentioned fusion and fiowability of the latter.

The polyethylene terephthalate tape employed in the preceding examples and the methods for manufacturing this particular tape are more particularly disclosed in U.S." Patents 2,465,319-Whinfield et al., issued March 22, 1949, and 2,779,684-Alles, issued January 29, 1957. The latter, Patent 2,779,684, recites in greater detail the processing of polyethylene terephthalate film employed in the manufacture of the aforesaid Cronar.

What I claim as new and desire to secure by Letters Patent of the United States is:

l. A composition of matter comprising a compatible mixture containing on a weight basis (1) from 10 to 98 parts of an organopolysiloxane in which at least 40 percent of the organo groups are aryl radicals and (2) from 2 to 90 parts of an aryl polymer selected from the class consisting of (a) polyarylene ethers and (Z1) mixtures of a polyarylene ether and a polystyrene material.

2. A thermoplastic composition of matter comprising a compatible mixture of ingredients containing on a weight basis (1) from 10 to 98 parts of an organopolysiloxane having the general formula RmSiO q where m is a value from 1 to 2.01, R is a monovalent organic radical, at least 40 percent of the said organic radicals being aryl radicals, the remaining radicals, if any, being of the class consisting of cycloalkyl, arkyl, alkyl, haloaryl, alkaryl, and aralkyl radicals, and (2) from 2 to parts of a solid aryl polymer selected from the class consisting of (a) a polyphenylene ether composed of the repeating structural unit of the air was sufli bon radicals free of a tertiary alpha-carbon atom, aralkyl, alkaryl, and aryl radicals, and Q is a monovlent substituent which is the same as Q and in addition may be a hydrocarbonoxy radical tree of an aliphatic tertitary alphacarbon atom, and (b) mixtures of the polyphenylene ether and a polystyrene material.

3. A composition of matter comprising a compatible mixture of ingredients comprising on a weight basis (1) from to 98 parts of an organopolysiloxane having the general formula RmSiO where m is a value of from 1 to 2.01, R is a monovalent organic radical, at least 40 percent of the said organic radicals being aryl radicals, the remaining radicals, if any, being selected from the class consisting of aryl, cycloalkyl, alkyl, haloaryl, alkaryl, and aralkyl radicals and (2) from 2 to 90 parts of a solid polyphenylene ether composed of the repeating structural unit l Col L 1.

wherein the oxygen atom of one unit is connected to the benzene nucleus of the adjoining unit, q is a positive integer, Q is a monovalent substituent selected from the class consisting of hydrogen, halogen, aliphatic hydrocarbon radicals free of a tertiary alpha-carbon atom, aralkyl, alkaryl, and aryl radicals, and Q is a monovalent substituent which is the same as Q and in addition may be a hydrocarbonoxy radical free of an aliphatic tertiary alphacarbon atom.

4. A composition of matter comprising a mixture of ingredients comprising on a Weight basis (1) from 10 to 98 parts of a thermoplastic organopolysiloxane having the general formula RmSiO 4.1m

where m is a value of from 1 to 2.01, R is a monovalent organic radical, at least 40 percent of the said organic radicals being aryl radicals, the remaining radicals, if any, being selected from the class consisting of aryl, cycloalkyl, alkyl, haloaryl, alkaryl, and arlkyl radicals and (2) from 2 to 90 parts of a mixture of ingredients comprising (a) a polyphenylene ether composed of the repeating structural unit Q l l -Q i Q .in

wherein the eoxygen atom of one unit is connected to the benzene nucleus of the adjoining unit, q is a positive integer, Q is a monovalent substituent selected from the class consisting of hydrogen, halogen, aliphatic hydrocarbon radicals tree of a tertiary alpha-carbon atom, arlkyl, alkaryl, and aryl radicals, and Q is a monovalent substituent which is the same as Q and in addition may be a hydrocarbonoxy radical free of an aliphatic tertiary alphacarbon atom, and (b) a solid polystyrene.

5. A composition of matter comprising a compatible mixture containing on a weight basis (1) from 10 to 98 parts of a thermoplastic diphenyl polysiloxane having a ratio of from 2 to 2.01 phenyl groups per silicon atom and having a liquid point of at least 75 C. and (2) from 2 to parts of a thermoplastic polyphenylene ether composed of the repeating structural unit Q Q iq wherein the oxygen atom of one unit is connected to the benzene nucleus of the adjoining unit, q is a positive integer, Q is a monovalent substituent selected from the class consisting of hydrogen, halogen, aliphatic hydrocarbon radicals free of a tertiary alpha-carbon atom, aralkyl, alkaryl, and aryl radicals, and Q is a monovalent substituent which is the same as Q and in addition may be a hydrocarbonoxy radical free of an aliphatic tertiary alphacarbon atom.

6. A composition of matter comprising a compatible mixture of ingredients comprising on a weight basis (1) from 10 to 98 parts of an organopolysiloxane having the general formula where m is a value of from 1 to 2.01, R is a monovalent organic radical, at least 75 per cent of the said organic radicals being aryl radicals, the remaining radicals, if any, being selected from the class consisting of aryl, cycloalkyl, alkyl, haloaryl, alkaryl, and aralkyl radicals and (2) from 2 to 90 parts of a solid polyphenylene ether composed essentially of the repeating structural unit 7. A composition of matter comprising a compatible mixture of ingredients comprising on a weight basis (1) from -10 to 98 parts of an organopolysiloxane having the general formula RmSiO where m is a value of from 1 to 2.01, R is a monovalent organic radical, at least 75 percent of the said organic radicals being aryl radicals, the remaining radicals, if any, being selected from the class consisting of aryl, alkyl, cycloalkyl, haloaryl, alkaryl and aralkyl radicals, and (2) from 2 to 90 parts of a mixture of ingredients comprising (a) solid polystyrene and (b) a solid polyphenylene ether composed essentially of the repeating structural unit the recurring structural unit i.. CH3 .i

9. A composition of matter comprising a compatible mixture of ingredients composed on a weight basis, of (1) from 10 to 98 parts of a polydiphenyl siloxane having a liquid point of around 75 C. and (2) from 2 to 90 parts of a mixture of ingredients comprising (a) solid polystyrene and (b) a solid polyphenylene ether composed essentially of the recurring unit i QJ 10. A recording medium comprising a supporting base member and a thermoplastic layer comprising a compatible mixture of ingredients comprising on a weight basis (1) from to 98 parts of an organopolysiloxane having the general formula where m is a value of from 1 to 2.01, R is a monovalent organic radical, at least 40 percent of the said organic radicals being aryl radicals, the remaining radicals, if any, being selected from the class consisting of aryl, alkyl, cycloalkyl, haloaryl, alkaryl, and aralkyl radicals and (2) from 2 to 90 parts of a solid aryl polymer selected from the class consisting of (a) a polyphenylene ether composed of the repeating structural unit l Q in wherein the oxygen atom of one unit is connected to the benzene nucleus of the adjoining unit, q is a positive integer, Q is a monovalent substituent selected from the class consisting of hydrogen, halogen, aliphatic hydrocarbon radicals free of a tertiary alpha-carbon atom, aralkyl, alkaryl, and aryl radicals, Q is a monovalent substituent which is the same as Q an in addition may be a hydrocarbonoxy radical free of an aliphatic tertiary alphacarbon atom, and (b) mixtures of (a) and a polystyrene material.

11. A recording medium comprising a supporting base member and a thermoplastic layer comprising a compatible mixture of ingredients comprising on a Weight basis (1) from 10 to 98 parts of an organopolysiloxane having the general formula RmSIO where m is a value of from 1 to 2.01, R is a monovalent organic radical, at least 40 percent of the said organic radicals being aryl radicals, the remaining radicals, if any, being selected from the class consisting of aryl, alkyl, cycloalkyl, haloaryl, alkaryl, and aralkyl radicals and (2) from 2 to 90 parts of a solid polyphenylene ether composed of the repeating structural unit l i l O i. Q .lq

wherein the oxygen atom of one unit is connected to the benzene nucleus of the adjoining unit, q is a positive integer, Q is a monovalent substituent selected from the class consisting of hydrogen, halogen, aliphatic hydrocarbon radicals free of a tertiary alpha-carbon atom, aralkyl, alkaryl, and aryl radicals, Q is a monovalent sub-, stituent which is the same as Q and in addition may be a hydrocarbonoxy radical having at least two carbon atoms and being free of an aliphatic tertiary alpha-carbon atom. 12. A recording medium comprising a base supporting member and a termoplastic layer comprising a compatible mixture of ingredients comprising on a weight basis (1) 22 from 10 to 98 parts of a thermoplastic organopolysiloxane having the general formula ltmsio T where m is a value of from 1 to 2.01, R is a monovalent organic radical, at least 75 percent of the said organic radicals being aryl radicals, the remaining radicals, if any, being selected from the class consisting of cycloalkyl, aryl, alkyl, haloaryl, alkaryl, and aralkyl radicals, and (2) from 2 to 90 parts of a polyarylene polymer mixture comprising (a) a solid polyphenylene ether composed of the repeating structural unit wherein the oxygen atom of one unit is connected to the benzene nucleus of the adjoining unit, q is a positive integer, Q is a monovalent substituent selected from the class consisting of hydrogen, halogen, aliphatic hydrocarbon radicals free of a tertiary alpha-carbon atom, aralkyl, alkaryl, and aryl radicals, and Q is monovalent substituent which is the same as Q and in addition may be a hydrocarbonoxy radical free of an aliphatic tertiary alphacarbon atom, and (b) a solid polystyrene.

13. A recording medium comprising a base supporting member and a thermoplastic layer comprising a compatible mixture of ingredients comprising on a Weight basis (1) from 10 to 98 parts of a thermoplastic diphenyl polysiloxane having a liquid point of at least 75 C., and (2) from 2 to 90 parts of a thermoplastic polyphenylene ether composed of the repeating structural unit porting member, (B) a thermoplastic layer comprising a compatible mixture of ingredients comprising on a weight basis (1) from 10 to 98 parts of an organopolysiloxane having the general formula RmSIO wherein the oxygen atom of one unit is connected to the benzene nucleus of the adjoining unit, q is a positive integer, Q is a monovalent substituent selected from the class consisting of hydrogen, halogen, aliphatic hydrocarbon radicals free of a tertiary alpha-carbon atom, aralkyl, alkaryl, and aryl radicals, and Q is a monovalent substituent which is the same as Q and in addition may be a hydrocarbonoxy radical free of an aliphatic tertiary alphacarbon atom, and (b) mixtures of (a) and a polystyrene material, and (C) an intermediate conducting layer selected from the class consisting of metals, metal oxides, and metal salts in contact with both the base member and the thermoplastic layer.

15. A recording medium comprising a supporting base member, a thermoplastic layer comprising a compatible mixture of ingredients composed on a Weight basis of (1) from to 98 parts of a polydiphenyl siloxane having a liquid point of at least 75 C., and (2) from 2 to 90 parts of a solid polystyrene of a molecular Weight of from 2,000 to 100,000, and an intermediate conducting layer selected from the class consisting of metals, metal oxides, and metal salts in contact with the base member and the thermoplastic layer.

16. A recording medium comprising a supporting base member, a thermoplastic layer comprising a compatible mixture of ingredients comprising on a Weight basis (1) from 10 to 98 parts of a polydiphenyl siloxane having a liquid point of at least 75 C. and (2) from 2 to 90 parts of a solid polyphenylene ether composed essentially of the recurring unit.

l lol Q. l

curring unit l 1 Q Hz J.

the total weight of (2) and (3) being equal on a weight basis to form 2 to 90 parts, and an intermediate conducting layer in direct contact with the base member and the thermoplastic layer selected from the class consisting of metals, metal oxides, and metal salts.

18. A recording medium comprising (1) a polyethylene terephthalate supporting base member, (2) an outer thermoplastic layer comprising a compatible mixture of ingredients comprising on a Weight basis (a) from 10 to 98 parts of a polydiphenyl siloxane having a liquid point of at least 75 C. and (b) from 2 to 90 parts of solid polystyrene, and (3) an intermediate conducting layer comprising chromium in direct contact With the polyethylene terephthalate and the thermoplastic layer.

19. An optically clear recording medium comprising a supporting base member of polyethylene terephthalate, an outer thermoplastic layer comprising a compatible mixture of ingredients comprising on a Weight basis (a) from 10 to 98 parts of a polydiphenyl siloxane and (b) from 2.4 2 to 90 parts of a polyphenylene ether composed essentially of the recurring unit l 101 L Z. l

and an intermediate transparent chromium metallic layer in direct contact with the base member and the thermoplastic layer.

20. A recording medium comprising a supporting base member, an outer thermoplastic layer comprising a compatible mixture of ingredients comprising on a Weight basis (a) from 10 to 98 parts of a polydiphenyl siloxane, (b) solid polystyrene, and (c) a solid polyphenylene ether composed essentially of the recurring unit r I l l I l CH3 the weight of (b) and (0) being equal on a weight basis to from 2 to 90 parts, and an intermediate chromium layer in direct contact with both the base member and the thermoplastic layer.

21. An optically clear recording medium comprising a base supporting member of polyethylene terephthalate, an outer thermoplastic layer comprising a compatible mixture of ingredients comprising on a Weight basis (a) from 10 to 98 parts of a polydiphenyl siloxane and (b) from 2 to 90 parts of solid polystyrene, and an intermediate transparent conducting layer of cu'prous iodide, the said conducting layer being in direct contact with the base member and the thermoplastic layer.

22. A recording medium comprising (1) a polyethylene terephthalate base member, an outer thermoplastic layer comprising a compatible mixture of ingredients comprising on a weight basis (a) from 10 to 98 parts of a polydiphenyl siloxane having a liquid point of at least 75 C. and (b) from 2 to 90 parts of solid polystyrene, and an intermediate transparent conducting layer comprising iron in direct contact with the polyethylene terephthalate base member and the thermoplastic layer.

23. An optically clear recording medium comprising a base member of polyethylene terephthalate, an outer thermoplastic layer comprising a compatible mixture of ingredients comprising on a weight basis (a) from 10 to 98 parts of a polydiphenyl siloxane and (b) from 2 to 90 parts of a solid polyphenylene ether composed essentially of the recurring unit where m is a value of from 1 to 2.01, R is a monovalent organic radical, at least percent of the said organic radicals being aryl radicals, the remaining radicals, if any, being selected from the class consisting of cycloalkyl, aryl, alkyl, haloaryl, alkaryl, and aralkyl radicals and (2) from 2 to parts of a solid aryl polymer selected I. Q .L

wherein the oxygen atom of one unit is connected to the benzene nucleus of the adjoining unit, q is a positive integer, Q is a monovalent substituent selected from the class consisting of hydrogen, halogen, aliphatic hydrocarbon radicals free of a tertiary alpha-carbon atom, aralkyl, alkaryl, and aryl radicals, and Q is a monovalent substituent which is the same as Q and in addition may be a hydrocarbonoxy radical free of an aliphatic tertiary alpha-carbon atom, and mixtures of (a) and (b) and (C) an intermediate transparent conducting layer selected from the class consisting of metals, metal oxides, and metal salts in direct contact with the polyethylene terephthalate and the thermoplastic layer.

25. A recording medium as in claim 24 in which the conducting layer is a thin layer of chromium.

26. A recording medium as in claim 24 in which the conducting layer is a thin layer of iron.

27. A recording medium as in claim 24 in which the thermoplastic layer is composed of a compatible mixture of ingredients comprising a polydiphenyl siloxane, solid polystyrene, and a solid polyphenylene ether composed of the recurring structural unit 28. A recording medium as in claim 24 in which the thermoplastic layer is composed of a compatible mixture of a polydiphenyl siloxane and solid polystyrene.

29. A recording medium as in claim 24 in which the thermoplastic layer is composed of a compatible mixture of ingredients comprising a polydiphenyl siloxane and a solid polyphenylene ether composed essentially of the recurring structural unit l 101 Q. l

30. An optically clear recording medium comprising 26 (A) a base member of polycarbonate resin, (B) a thermoplastic layer comprising a compatible mixture of ingredients comprising on a weight basis (1) from 10 to 98 parts of an organopolysiloxane having the general formula RmSiO km Where m is a value of from 1 to 2.01, R is a monovalent organic radical, at least percent of the said organic radicals being aryl radicals, the remaining radicals, if any being selected from the class consisting of cycloalkyl, aryl, alkyl, haloaryl, alkaryl, and aralkyl radicals and (2) from 2 to parts of a solid aryl polymer selected from the class consisting of (a) a polystyrene, (b) a polyphenylene ether composed of the repeating structural unit l 3.1 Q l wherein the oxygen atom of one unit is connected to the benzene nucleus of the adjoining unit, q is a positive integer, Q is a monovalent substituent selected from the class consisting of hydrogen, halogen, aliphatic hydrocarbon radicals free of a tertiary alpha-carbon atom, aralkyl, alkaryl, and aryl radicals, and Q is a monovalent substituent which is the same as Q and in addition may be a hydrocarbonoxy radical free of an aliphatic tertiary alpha-carbon atom, and (0) mixtures of (a) and (b), and (C) an intermediate transparent conducting layer selected from the class consisting of metals, metal oxides, and metal salts in direct contact with the polycarbonate resin base member and the thermoplastic layer.

References Cited in the file of this patent UNITED STATES PATENTS 2,470,772 Haas May 24, 1949 2,494,329 Carlin Jan. 10, 1950 2,635,060 Cheronis et a1 Apr. 14, 1953 2,704,265 Lyon Mar. 15, 1955 2,748,288 Saulnier May 29, 1956 2,884,388 Hedlund Apr. 28, 1959 FOREIGN PATENTS 565,863 Canada Nov. 1'1, 1958 

17. A RECORDING MEDIUM COMPRISING A SUPPORTING BASE LAYER, A THERMOPLASTIC LAYER COMPRISING A COMPATIBLE MIXTURE OF INGREDIENTS COMPRISING ON A WEIGHT BASIS (1) FROM 10 TO 98 PARTS OF A POLYDIPHENYL SILOXANE HAVING A LIQUID POINT OF AT LEAST 75*C., (2) SOLID POLYSTYRENE, AND (3) A SOLID POLYPHENYLENE EHTER COMPOSED ESSENTIALLY OF THE RECURRING UNIT. 